Cast spun (cast+spun) aluminum alloy hubs are universally applied in the field of cars due to the advantages of quick heat dissipation, light weight, energy conservation, good comfort, attractive appearance and the like. During processing, the spoke and the thick and large rim are formed by low pressure casting, and then the cast rim is processed to the appropriate size and shape via strong hot spinning. After hot spinning, most metal grains of the rim are thinned, and the rim has obvious fiber textures, so that the overall strength and corrosion resistance of the wheel are greatly improved. The power spinning process for the rim belongs to thinning spinning, and the deformation process is divided into a plurality of steps according to the deformation degree, that is, a plurality of spinning rollers are matched and move according to certain staggered distance and trajectory, so that the spun workpieces meet the requirements for size and quality.
During spinning, the spinning rollers and the high-temperature workpieces produce strong high-speed friction, the rotating speeds of the workpieces are 800 revolutions per minute, and the spinning rollers must keep the dimensional precision and the surface roughness under such condition so as not to fail early. The failing spinning roller leads to texture deformation and non-uniformity, performance decline and poor consistency of the spun part.
It is required that the spinning roller material can bear mechanical wear and a thin and closely attached oxide film can be formed on the friction surface of the spinning roller to keep a lubricating effect, thereby preventing adhesion between the spinning roller and the surface of the processed workpiece, and reducing damage caused by further oxidation of the surface of the spinning roller. As for a spinning roller working at a high temperature under a strong impact load, its high-temperature toughness at the working temperature must be considered.
Patents CN105506530A, titled Surface Composite Reinforcing Method for Mold and CN104762617A, titled Laser Repair Method for Mold disclosed by the State Intellectual Property Office disclose treatment of a laser cladding technology and an induction cladding and rolling hardening combined technology on the surfaces of molds. These technologies are not perfect enough for hardening spinning rollers in high-temperature and high-speed powerful friction, and may cause the phenomena of hardening layer drop, low strength, surface corrosion pits and the like. In order to improve the wear resistance, strength and toughness of the high-speed and high-speed spinning rollers, appropriate materials and reasonable production processes and thermal treatment methods are needed, so that the spinning rollers have high hardness, the composition, morphology and distribution of hardening phases such as carbides and the like in the materials are reasonable, corrosion can be prevented, good weldability is achieved, and the texture uniformity and performance consistency of the spun parts of the workpieces can thus be improved.